1. Field of the Invention
This invention relates in general to providing water in semi-arid and arid regions, more particularly to providing purified water from impaired water sources in semi-arid and arid regions, and most particularly to providing purified water from impaired water sources in semi-arid and arid regions through solar distillation.
2. Description of the Related Art
In previously filed application Ser. No. 10/729,265 for a solar distillation loop, to which this application is a continuation-in-part, problems related to exploiting certain impaired water sources in semi-arid and arid regions was discussed. These problems related to unacceptable water quality of many water sources in these regions and high energy/conveyance costs to use these water sources for irrigation or other purposes within these regions.
To address these issues, the inventor herein developed a solar distillation loop invention that was disclosed and claimed in the above referenced application. In general, operation of the invention works as follows.
A solar distillation loop is a chemical process that occurs in a drainage pipe system designed to purify salt water, or other impaired water, and distribute the purified water below the surface of the ground at a shallow depth for the purposes of subsurface irrigation or ground-water recharge. Alternatively, a slight variation in the drainage pipe system design redirects the purified water to a storage tank for use as a potable drinking water source.
The invention utilizes sea water, drainage water, sewage effluent, or other impaired water and converts this solution into pure water for use as a source of subsurface irrigation, ground-water recharge or as a source of drinking water. The purification process is a low energy method of water purification, because the water purification process requires solar energy for separation of impurities from the water, as well as the redistribution of the purified water. Solar energy is used as a source of thermal energy to evaporate water from the impaired water solution. Solar energy is also used to generate a direct-current power source to drive fans within the solar distillation loop to distribute the pure water vapor to an appropriate location for condensation and utilization.
The process of solar distillation of impaired water, where water vapor is evaporated from an impaired water body and condensed elsewhere, is carried out within a solar distillation loop. Within a solar distillation loop, the process of solar distillation is greatly accelerated due to: 1) the use of solar-powered fans within the solar distillation loop, and 2) the natural vertical thermal gradient that exists near the ground surface. The circulation created by the solar fans continually reduces the water vapor pressure above the impaired water, which accelerates water evaporation from the impaired water. The natural thermal gradient accelerates the condensation of pure water for the purposes of either subsurface irrigation, ground-water recharge, or a source of potable water.
In utilizing a solar distillation loop, the amount of impaired water that can be purified is directly related to the water surface area available for evaporation. Therefore, it is desired to provide a device and method for increasing the available surface area for evaporation within a solar distillation loop.